Author Topic: title edit: 1977 cb400/4 running issues. gahhh! help me!  (Read 3429 times)

0 Members and 1 Guest are viewing this topic.

3 sticks

  • Guest
title edit: 1977 cb400/4 running issues. gahhh! help me!
« on: July 08, 2006, 07:52:28 PM »
So I got this 77' cb400/4 from some guy..

It's in pretty ratty condition and so i stripped a lot of it down. (turn snigals, seat, tank, fenders, covers, old battery, ETC.)

I had to replace the ignition because the guy didn't have any keys (or a title or anything at all) (but get this - ORIGINAL TOOLKIT INCLUDED)

Anyway so i've finally gotten the electronics cleaned up to the point where I can stick in a key and the lights come up along with the clock lights etc. ;D

Now comes the problem: I still cant get the starter to do anything when I hit the button BUT it's not like it matters anyway because the carbs are pretty much solid. In fact the gas was still on when I picked up the bike. I shot a bunch of carb cleaner down the gas line in hopes to break up any gum but it seems my efforts have been fruitless because I eventually figured out that i really dont know a damn thing about these 400f carbs. :D ::)

The biggest problem is HOW DO I GET THEM OUT OF THE DANG BIKE!?

If I could just get them out then i would be home free... i've cleaned carbs before on other bikes so i'm familiar with the process.


Man I really need some input on this mess... :'(

-Will



p.s. i've already loosened up the metal clamps from the airbox and to the cylanders, and i've disconnected the airbox from the carbs even though it's still just sitting in the bike).
« Last Edit: July 11, 2006, 01:59:44 PM by 3 sticks »

Offline cbjunkie

  • Master
  • *****
  • Posts: 2,346
  • ...know what i'm sayin'?
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #1 on: July 08, 2006, 07:57:24 PM »
yo, sticks - do a search for info on this - also look in FAQs - there are a lot of threads giving tips and i think there may even be one or two archived in the FAQs page...

good luck
junkie...
1971 750K1
1972 CB350 (deceased)

sometimes naked, sometimes mad -
now the poet, now the fool -
thus they appear on earth,
the free men.

Offline Lumbee

  • Expert
  • ****
  • Posts: 1,498
    • My pics...
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #2 on: July 08, 2006, 08:03:31 PM »
...the carb rubbers on these bikes gets pretty hard over time.  You'v got two choices.

1-Use a screw driver or something to pry the rubber boots off the head.  This is cumbersome, and many times you end up mauling the boot, or bending or breaking the fins on the head, as thats what you will use for leverage.

2-What I like to do is use a heat gun ( you probably don't have one) to warm up the boots, this will soften up the rubber and make it possible (but sitll a bear) to remove them.  If yo have a hair dryer you could try that.

If this bike is in the shape you say sounds like you'll need a full overhaul of the fuel system...tank and carbs...good luck and keep us posted...
----------
"I'm not a welder, but I play one on HondaChopper.com"

Offline cbjunkie

  • Master
  • *****
  • Posts: 2,346
  • ...know what i'm sayin'?
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #3 on: July 08, 2006, 08:13:27 PM »
didn't somebody post some brilliant move involving a broomstick? i just can't remember what it was but it involved a "pop" as all the carbs came off at once...
1971 750K1
1972 CB350 (deceased)

sometimes naked, sometimes mad -
now the poet, now the fool -
thus they appear on earth,
the free men.

Offline Bob Wessner

  • "Carbs Suck!"
  • Really Old Timer ...
  • *******
  • Posts: 10,079
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #4 on: July 08, 2006, 08:22:33 PM »
This is the one I think you are referring to..

http://www.sohc4.us/forums/index.php?topic=9669.msg90781#msg90781
We'll all be someone else's PO some day.

3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #5 on: July 08, 2006, 08:56:04 PM »
lumbee - i'll definatley try that heat gun thing tomorrow

cbjunkie - I'm going to attemp the big stick procedure with a rag against the fins tomorrow

and bob - thanks for the link


If this bike is in the shape you say sounds like you'll need a full overhaul of the fuel system...tank and carbs...good luck and keep us posted...

I've got here some pictures I just took while we're on the subject. The tank actually looks really good inside. The bike spent most of its time under a tarp and the gas cap was latched closed, so anything thats not directly open to the elements is pretty good - like the tank or under the points cover.


3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #6 on: July 08, 2006, 08:58:50 PM »
2 more...

3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #7 on: July 08, 2006, 08:59:39 PM »
...and the last one.

Offline cbjunkie

  • Master
  • *****
  • Posts: 2,346
  • ...know what i'm sayin'?
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #8 on: July 08, 2006, 09:24:08 PM »
wow - nice tank...believe me i've seen, and agonized over alot worse...the outside of the last tank i worked on looked like the outside of your carbs!
1971 750K1
1972 CB350 (deceased)

sometimes naked, sometimes mad -
now the poet, now the fool -
thus they appear on earth,
the free men.

Offline JHansen

  • Enthusiast
  • **
  • Posts: 118
  • In a word... breathtaking
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #9 on: July 09, 2006, 06:08:57 AM »
OK, here is my question...

Who lets these bikes deteriorate to this state?

With a small amount of intelligence and elbow grease these bikes could stay looking nice forever, but no... people just trash them! #$%*s!

I know about the intelligence and elbow grease thing because I have little of it and all my bikes look cherry! ;D
'76 CB400f -cafe'd out
'75 CB400f -future project waiting in wings
'03 Yamaha V-Star Classic
'90 Honda VFR 750

Offline puppytrax

  • Expert
  • ****
  • Posts: 1,059
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #10 on: July 09, 2006, 06:30:36 AM »
OK, here is my question...

Who lets these bikes deteriorate to this state?

I can answer that (well, one answer anyway)...Someone who bought an old 80-something widow's left-over stock of used/salvaged bikes, and had to store them in an old 1880's warehouse, with holes in the roof, collapsed flooring, no electricity, no windows, no heat, and snow in the Winter...literally thousands of bikes (OK; maybe only one thousand)...and who is trying to make a living selling off bits & pieces and occasionally taking 3 or 4 bikes and making one runner (like the one shown) to sell...

No, it's not me...but I spent an hour and a half looking through those isles of old moldy Hondas and others...it's depressing, but at least they're not in a landfill...   :'(
...stock 1972 CB500 '500 Four' undergoing re-assembly...
...Stock 1972 CL450 'Scrambler' also being re-assembled...

Offline Lumbee

  • Expert
  • ****
  • Posts: 1,498
    • My pics...
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #11 on: July 09, 2006, 07:23:57 AM »
...def got yourself a project there 3sticks.  The motor does turn over right?  Have you done a compression test?  May be worth doing before you get to far.

Use the heat gun to warm the boots in conjunction with broom stick trick and they should come off.  Also I'd loosen the clamps on both sides of the boots.  Sometimes its easier for the carbs to pop off on the carb side, and sometimes on the head side.
----------
"I'm not a welder, but I play one on HondaChopper.com"

Max Power

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #12 on: July 09, 2006, 07:52:50 AM »
Looking at that broomstick thread, I am realizing a lot of people are strugging to get their carbs off a lot more than I am. Are the 500's and 750's much harder than the 400's?

3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #13 on: July 09, 2006, 08:54:11 AM »
jhansen - I'll tell you EXACTLY who lets these bikes get to this kind of state. (at least around my area) It's all these idiots who treat motorcycles like toys. They dont take care of them, and just let them outside to rot and when it gets to the point of (they've lost the keyes, the title, the toolkit, the bike is rusty, ruined tires, doesn't run, etc.), and they just get a new one! It's the same exact people who just go out and buy some harley or harley-esque chrome peice of garbage with no style or feeling! And one last thing on that subject- i'm almost POSITIVE that when this whole cruiser fad runs out in 15 or 20 years youre going to be able to pick up some rusty, non-running, no keys, no title, kawasaki nomad; honda vtx, or victory mototrycle for $200. (of course the HARLEYs themselves will still be rediculously over-priced because of the name.)

lumbee- the motor turns over nicley. It SOUNDS like its got good compression just by kicking it over and hearing the nice WOOF WOOF WOOF come out of the header pipes. I've got a tester though and i'm thinking about doing a real test on it as well. Shouldn't the motor be hot for a real set of readings though?
« Last Edit: July 09, 2006, 08:56:21 AM by 3 sticks »

supersport_CB400F

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #14 on: July 09, 2006, 10:09:11 AM »
I wish you luck with that project, I pushed backwards and down my 400 carbs and they plopped off with not to much of a fight…. not the struggle I expected after sitting for so many years.

3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #15 on: July 09, 2006, 05:31:14 PM »
well ive got the carbs almost clean i think, but the starter still doesnt work, and i dont know if the coils are working either. I checked the points, and i got spark when i lifted the contacts, so at least somthing works. Any ideas on the coils or the starter anyone?

thanks again..will

Offline Bodi

  • Really Old Timer ...
  • *******
  • Posts: 5,697
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #16 on: July 09, 2006, 05:48:48 PM »
For the starter -
There's an interlock that keeps you from starting it if it's in gear with the clutch out. The clutch switch is the over-ride, there's a diode in the neutral lamp circuit as well.
Try the starter with the clutch lever pulled in. If it goes, you may just have a blown diode which is not unusual.
If not, get the "real" circuit diagram from the Honda owners manual or the Honda shop manual. Clymer and Haynes electrical diagrams are incomplete and misleading.

Offline cmorgan47

  • Hot Shot
  • ***
  • Posts: 657
  • smaller, lighter, quicker
    • theundergr0und
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #17 on: July 09, 2006, 06:42:16 PM »
i just wnet through the ignition on this bike. 

to test the coils, get a multimeter and stick one end in each of the spark plug wires for each coil (ie 1-4 and 2-3)  you should get continuity and a fair bit of resistance.

have you checked to see that the breakers are opening and closing when you rotate the drive shaft?  take a 15mm wrench and rotate it clockwise till you see 1.4 or 2.3 in the window, the cooresponding breaker should be open a little at that point.
i love babies...
with a nice chianti sauce and a side of fava beans

Offline JHansen

  • Enthusiast
  • **
  • Posts: 118
  • In a word... breathtaking
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #18 on: July 09, 2006, 07:01:39 PM »
OK men, I've been thinking and I think I have the answer.

I think the federal government should setup some sort of agency for us, similar to child protective services. Only in our case, it'd be motorcycle protective services. I will be happy to run the Kalamazoo MPS office.  ;D

Basically, if an MPS agent observes a bike being neglected (I'm picturing a handlebar sticking out of a snowdrift or a rear fender peeking out from under a mountain of junk) the agency has the right to immediately confiscate the bike in question and find a home for it where it will be loved and appreciated. No cruiser for us to patrol in, no way. The feds can supply each agent with any SOHC of their choice. Dang! Why am I not working in Washington! :)

I'm getting my pen out, everyone... write your Congressmen! :)

JH
'76 CB400f -cafe'd out
'75 CB400f -future project waiting in wings
'03 Yamaha V-Star Classic
'90 Honda VFR 750

3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #19 on: July 09, 2006, 10:51:50 PM »
ITS ALIVE!!!!!!

of course, with no muffler it also sounds pretty freakin mean.

I will post more when i settle myself down...

3 sticks

  • Guest
Re: 1977 cb400/4 Carbourateur issues. gahhh! help me!
« Reply #20 on: July 11, 2006, 01:58:17 PM »
Well anyway; I took it out on a 2 mile ride today, and I have good news! I'm still alive!  ;D

There are a handful of problems that i'm still sorting out. Before I list them i'm going to say a few things to give you all an idea of the current situation:

1: I don't beleive the carbs are 100% yet. When I turn the gas on, gas pretty much pours out of the overflow tubes (?) that come out of the bottom of the bowls.
2: The airbox isn't back in yet because I didnt want to pound this whole thing together and then find out I had to take the carbs out again because they were still dirty.
3: There is no exhaust. Just header pipes that come down and stop at a rusty jagged hole where an exhaust once resided.
4: I have not added any oil. I just checked to make sure it had any to begin with. (It was quite low; not surprising since the whole area around the shifter seal is completley covered with oil and dirt.)

NOW;

To start the bike cold, I have to turn the choke on all the way, open the throttle all the way, and then kick it once. I also cannot let the rpms drop below 2500 or 3000, or it will stall. Now today when I drove it around the neighborhood a little, I got it to the point where I could let the rpms drop all the way to 1000 and then not too long after that, I had to turn the choke off, as it was beginning to feel more like a normal motorcycle. Another thing to remember is that it was getting kind of hot by now (the motor) even though its only been on for about 5 minuites.

So anyway, the whole point of this is the following:

In all of the accumulated experience contained in the brains belonging to this forum, may I please have the assistance of you all by telling me what exactly is going on, whats causing it, and what can be done to fix it? If I havn't been 100% clear on any point, just ask me again in a way that a 6 year old could understand, and I will answer in the best of my abilities. Also, if I come up with any other points of interest, I will bring them up asap.

Thank you all very much in advance!!

will

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,805
Re: title edit: 1977 cb400/4 running issues. gahhh! help me!
« Reply #21 on: July 11, 2006, 05:16:44 PM »
Quote
1: I don't beleive the carbs are 100% yet. When I turn the gas on, gas pretty much pours out of the overflow tubes (?) that come out of the bottom of the bowls.

Float height set wrong, Dirt/debris blocking the float valves from closing. Cracks in the stand pipe of the float bowls.

Do you have a shop manual?

Quote
2: The airbox isn't back in yet because I didnt want to pound this whole thing together and then find out I had to take the carbs out again because they were still dirty.

The airbox and filter deepen the pressure dip in the carb throats when the engine is running.  This causes the fuel jets to provide more fuel to the mix.  This may be more dramatic at idle since there is very little air supplied by the carbs at idle and small changes in fuel metering make a bigger difference in run performance.  Since you have no air box, and the carbs are likely tuned for them to be there, your engine is likely running very lean.  A cold engine doesn't atomize fuel very well and needs a richer mixture to run properly.  Hot engines are more efficient with fuel.  And, need less fuel in the mix to run well.
If you ever want your carbs to run well with a filter, tune your carbs to run well with it installed. 

Quote
3: There is no exhaust.
A similar issue exists with the exhaust.  Muffler back pressure effects airflow and mixture rates required of the carburetor.  Tune carburetors with the exhaust system you wish to run on the street. (Or, whatever your planned operational mode is going to be.

Quote
4: I have not added any oil.
Dirty oil is one thing.  No, or low oil is quite another.  Oil is the blood of the engine.  Run without, it will die.  Run it dirty, it will die earlier than if it had clean oil.  If you want more major repairs to be made to the bike, keep chinzing on the oil.  Even at $10 a quart.  It is cheaper than replacement bearings, pistons, rings etc.
Oil is even more important on an engine running hot/lean.  Once the pistons and rings seize in the bore, it will never perform to full potential without parts replacement.

Want to know what it is like?  Go with out water or fluids for three days and see if you feel like your old chipper self.  Unlike you, though, the engine is not self repairing.

It sounds like you have it running well enough to determine it can be resurrected.  Now it is time too make a commitment and get the parts and supplies required to make it a whole bike.  Or, flog it till it's time to throw it away.

Best of luck!


Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.